function [mass,S] = getParams()
    % RLV
    mass = 104305;
    S = 391.22;
    % earth
    R0 = 6378137;
    g0 = 9.81;
    rho0 = 1.2256;
    hs = 7254.24;
    N = 200; % 离散点个数
    delta = 1/N; % 步长
    epsilon = 1; % 收敛阈值
    max_k = 10; % 容许最大迭代次数
    deg2rad = pi/180;
    rad2deg = 180/pi;
    alpha_max = 25;
    sigma_max = 90;
end